<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8" />
        <meta http-equiv="X-UA-Compatible" content="IE=edge" />
        <meta name="viewport" content="width=device-width, initial-scale=1.0" />
        <title>拖动模块框</title>
        <style>
            .login-header {
                width: 100%;
                text-align: center;
                height: 30px;
                font-size: 24px;
                line-height: 30px;
            }
            ul,
            li,
            ol,
            dl,
            dt,
            dd,
            div,
            p,
            span,
            h1,
            h2,
            h3,
            h4,
            h5,
            h6,
            a {
                padding: 0px;
                margin: 0px;
            }
            .login {
                display: none;
                width: 512px;
                height: 280px;
                position: fixed;
                border: #ebebeb solid 1px;
                left: 50%;
                top: 50%;
                background: #ffffff;
                box-shadow: 0px 0px 20px #ddd;
                z-index: 9999;
                /* z-index让其显示在最上层 */
                transform: translate(-50%, -50%);
                /* transform允许旋转 缩放 倾斜 平移给定元素 */
            }
            .login-title {
                width: 100%;
                margin: 10px 0px 0px 0px;
                text-align: center;
                line-height: 40px;
                height: 40px;
                font-size: 18px;
                position: relative;
                cursor: move;
            }
            .login-input-content {
                margin-top: 20px;
            }
            .login-button {
                width: 50%;
                margin: 30px auto 0px auto;
                line-height: 40px;
                font-size: 14px;
                border: #ebebeb 1px solid;
                text-align: center;
            }
            .login-bg {
                display: none;
                width: 100%;
                height: 100%;
                position: fixed;
                top: 0px;
                left: 0px;
                background: rgba(0, 0, 0, 0.3);
            }
            a {
                text-decoration: none;
                color: #000000;
            }
            .login-button a {
                display: block;
            }
            .login-input input.list-input {
                float: left;
                line-height: 35px;
                height: 35px;
                width: 350px;
                border: #ebebeb 1px solid;
                text-indent: 5px;
            }
            .login-input {
                overflow: hidden;
                margin: 0px 0px 20px 0px;
            }
            .login-input label {
                float: left;
                width: 90px;
                padding-right: 10px;
                text-align: right;
                line-height: 35px;
                height: 35px;
                font-size: 14px;
            }
            .login-title span {
                position: absolute;
                font-size: 12px;
                right: -20px;
                top: -30px;
                background: #ffffff;
                border: #ebebeb solid 1px;
                width: 40px;
                height: 40px;
                border-radius: 20px;
            }
        </style>
    </head>
    <body>
        <div class="login-header"><a id="link" href="javascript:;">点击，弹出登录框</a></div>
        <div id="login" class="login">
            <div id="title" class="login-title">
                登录会员
                <span><a id="closeBtn" href="javascript:void(0);" class="close-login">关闭</a></span>
            </div>
            <div class="login-input-content">
                <div class="login-input">
                    <label>用户名：</label>
                    <input
                        type="text"
                        placeholder="请输入用户名"
                        name="info[username]"
                        id="username"
                        class="list-input"
                    />
                </div>
                <div class="login-input">
                    <label>登录密码：</label>
                    <input
                        type="password"
                        placeholder="请输入登录密码"
                        name="info[password]"
                        id="password"
                        class="list-input"
                    />
                </div>
            </div>
            <div id="loginBtn" class="login-button">
                <a href="javascript:void(0);" id="login-button-submit">登录会员</a>
            </div>
        </div>
        <!-- 遮盖层 -->
        <div id="bg" class="login-bg"></div>
        <script>
            // 1获取元素
            var login = document.querySelector('.login');
            var mask = document.querySelector('.login-bg');
            var link = document.querySelector('#link');
            var closeBtn = document.querySelector('#closeBtn');
            var title = document.querySelector('#title');
            // 2. 点击弹出层这个链接 link  让mask 和login 显示出来
            link.addEventListener('click', function () {
                mask.style.display = 'block';
                login.style.display = 'block';
            });
            //3 点击closeBtn就隐藏mask和login
            closeBtn.addEventListener('click', function () {
                mask.style.display = 'none';
                login.style.display = 'none';
            });
            //4 开始拖拽:拖拽有三个过程组成 鼠标按下mousedown  鼠标移动mouseover  鼠标松开mouseup
            // 只要将鼠标在页面的位置-鼠标在盒子的位置 赋值给盒子即可
            //(1)当我们鼠标按下， 就获得鼠标在盒子内的坐标
            title.addEventListener('mousedown', function(e) {
            var x = e.pageX - login.offsetLeft;
            var y = e.pageY - login.offsetTop;
            // (2) 鼠标移动的时候，把鼠标在页面中的坐标，减去 鼠标在盒子内的坐标就是模态框的left和top值
            document.addEventListener('mousemove', move)

            function move(e) {
                login.style.left = e.pageX - x + 'px';
                login.style.top = e.pageY - y + 'px';
            }
            // (3) 鼠标弹起，就让鼠标移动事件移除
            document.addEventListener('mouseup', function() {
                document.removeEventListener('mousemove', move);
            })
        })

        </script>
    </body>
</html>
